This invention relates generally to the field of power transfer, and more particularly, is directed to a power transfer device incorporating ball action or some other interposed reduced friction material such as rollers, liquid or gases.
It has been the common practice in the past to employ gear systems to transfer energy from one shaft to a second shaft which is angularly oriented with respect to the first shaft. Worm gearing has usually been employed for obtaining large speed reduction between non-intersecting shafts which function at an angular relationship. When a gear engages a straight worm, that is, a worm wherein the outer periphery of all of the teeth are formed of the same diameter, the combination of a gear and a straight worm is usually known as "single enveloping worm gearing". In another system of the type wherein the worm is configured to a shape wherein the cross sectional diameter at the ends of the worm is greater than the cross sectional diameter at its middle, and wherein the mean worm diameter of the worm teeth transcribe an arc which is equal to the arc of a segment of the worm gear drawn through the throat diameter, the combination of a gear and such a worm is known as "double enveloping worm gearing".
One of the most popular power transfer sytems in general use throughout the world today comprises the differential gear employed for use with automobiles. In this system, the differential gears are mounted within a rotatable box frame which is fixedly connected to a large gear, generally designated as the ring gear. The ring gear meshes with a pinion gear which is usually of the bevel pinion type and which is employed to transmit power from the drive shaft to the differential gear box through an angle of ninety degrees. It is common practice to employ helical teeth on both the pinion and on the ring gear in this application.
Ball type power transfer systems in general are known as exemplified in U.S. Pat. Nos. 3,718,051, 2,764,030 and 2,159,325. These devices are considerably different from the instant device in that they do not teach cooperating grooves set at an angular relationship, they do not show hourglass shaped component parts and the use of toothless interacting parts.
In all systems wherein power is transmitted from one shaft to another shaft through ninety degrees by employing worm or bevel gear systems, the power transfer takes place at relatively low efficiency in view of the frictional engagement of the various gear teeth. In the case of the automobile differential system, the frictional losses occasioned by the frictional engagement of the gears is dissipated as heat which is absorbed by the rear axle lubricant, which is radiated to the atmosphere by the component parts or which is revealed as attrition, wear and/or deterioration of the component parts.